Gamboa Amanda, Branscum Adam J, Olson Dawn A, Sattgast Lara H, Iwaniec Urszula T, Turner Russell T
Skeletal Biology Laboratory, School of Biological and Population Health Sciences, Oregon State University, Corvallis, OR 97331, USA.
Biostatistics Program, School of Biological and Population Health Sciences, Oregon State University, Corvallis, OR 97331, USA.
Bone Rep. 2021 Feb 14;14:100755. doi: 10.1016/j.bonr.2021.100755. eCollection 2021 Jun.
Mechanical loading of the skeleton during normal weight bearing plays an important role in bone accrual and turnover balance. We recently evaluated bone microarchitecture in the femoral head in 5.6-week-old male Sprague Dawley rats subjected to a 4-day spaceflight aboard STS-41. Compared to weight bearing ground controls, cancellous bone volume fraction was dramatically lower in animals subjected to microgravity. The effects of spaceflight on the rat skeleton are potentially influenced by factors such as age, duration of flight, strain and sex. To test the generalizability of our initial observation, we evaluated archived proximal femora from two additional spaceflight missions: a 10-day mission (STS-57) with 7.5-week-old male Fisher 344 rats, and a 14-day mission (STS-62) with 12-week-old ovariectomized (ovx) female Fisher 344 rats. Cancellous microarchitecture and cortical thickness were assessed using x-ray microtomography/microcomputed tomography. In male rats, cancellous bone volume fraction (bone volume/tissue volume) was lower in flight animals compared to flight controls, but differences were not significant compared to baseline. In ovx female rats, cancellous bone volume fraction was lower in flight animals compared to flight controls and baseline, indicating net bone loss. Cortical thickness did not differ among groups in either experiment. In summary, findings from three separate studies support the conclusion that spaceflight results in cancellous osteopenia in femoral head of growing rats.
在正常负重过程中，骨骼的机械负荷在骨量积累和周转平衡中起着重要作用。我们最近评估了5.6周龄雄性Sprague Dawley大鼠在STS - 41上进行4天太空飞行后股骨头的骨微结构。与负重地面对照组相比，经历微重力的动物松质骨体积分数显著降低。太空飞行对大鼠骨骼的影响可能受年龄、飞行持续时间、品系和性别等因素影响。为了检验我们初步观察结果的普遍性，我们评估了另外两次太空飞行任务中存档的近端股骨：一次是7.5周龄雄性Fisher 344大鼠的10天任务（STS - 57），另一次是12周龄去卵巢（ovx）雌性Fisher 344大鼠的14天任务（STS - 62）。使用X射线显微断层扫描/微计算机断层扫描评估松质骨微结构和皮质厚度。在雄性大鼠中，与飞行对照组相比，飞行动物的松质骨体积分数（骨体积/组织体积）较低，但与基线相比差异不显著。在去卵巢雌性大鼠中，与飞行对照组和基线相比，飞行动物的松质骨体积分数较低，表明存在净骨质流失。在两个实验中，各组之间的皮质厚度均无差异。总之，三项独立研究的结果支持以下结论：太空飞行会导致生长中大鼠股骨头出现松质骨减少。
